COMMUNITY FORUM

thermostat question

I was reviewing the documentation of my furnace (TempStar), and it says that it is a 2-phase gas furnace.

I then looked at my existing thermostat which is a RobertShaw non-programmable (model 9500).

I don't think my current thermostat is designed for a 2-phase furnace and in fact there is only a single W terminal rather than W1 and W2. In addition there is a jumper from RC to RH and the wire is going to RC. There also is a G and a Y wire, the B and O terminals are left open.

That all being said, by heating works fine, and I have not had any problems in the 1.5 years that I have lived in my place.

So the question is can I get a similar thermostat that has a single W terminal? I don't even think that I have two W wires coming out of the wall.....

It sounds more like you have a two STAGE furnace. IF its a two stage furnace, you should just pick up a two stage thermostat.

If you can find a two Stage thermostat, you may be able to order one on the internet.

A two stage furnace basically has two separate burner operations, low heat and high heat. Usually the burners will operate on a call for heat for about the first 15 minutes, then if the room temperature is not satisfied it will kick into the second stage burner operation. Just do a little more research to find that two stage thermostat, one thing tho-when you remove your existing thermostat you need to have an existing second stage wires to stat. You need a w & w1 or a w1 & w2 existing connection. If you dont have the extra wire you need a service tech outthere to connect the second stage in the furnace or possibly bring you a new cable with enough wires to power up the second stage operation. on some furnaces you can override the first stage internally but why.

even though things are working fine, do I need to get a 2 stage thermostat?

there is not a second W wire to put into the thermostat, and i'm not sure that i want to make the investment for a tech to come out and rewire things - do you really think it's worth it - my condo is pretty small, and heating needs are currently satisfied pretty easily.

If it works dont change it! There is no reason you have to change it out, unless the unit does not operate, I mean the furnace may have a built in overide that automatically changes it two a single stage unit with a simple flick of a switch on the circuit board. Again you may need a tech outhere for that, but hey if its wirking and there seems to be no problems, I would not fool with it. Good luck